Guard for sewing machines



March 18, 1952 o. M. HOLMES GUARD FOR SEWING MACHINES Filed Dec. 5, 1949 [Cl/i912 0t is M Holmes Patented Mar. 18, 1952 GUARD FOR SEWING MACHINES Otis M. Holmes, Beverly, Mass, assignor to United .Shoe Machinery Corporation, Flemington, N. 3.,

a corporation of New Jersey.

Application December 3, 1942, Serial No. 136,903

1 The present invention relates to improvements in protective guards for shoe sewing machines, particularly those having individual electric motor power drivers, in which the driving connections including rotating pulleys and moving belts, introduce an element of hazard through accidental contact therewith. As hereinafter illustrated the machine is of the type disclosed in United States Letters Patent No. 710,612, granted October 7, 1902, and No. 885,378, granted April 21, 1908, both upon applications of Everett P. Richardson.

The machine of Patent No. 885,378 includes a standard or'column mounted on a base and provided with a sewing head at its upper end. The sewing head has within it the usual stitch forming devices actuated by a main sewing shaft having mounted at its rearward end a two-speed clutch and brake mechanism for controlling the speed of sewing and for bringing the machine to rest with the stitch forming devices in the desired relationship. The clutch includes a pair of loose pulleys driven by belts extending to the base of the machine. At the lower portion of the machine column is mounted a stud shaft having power driven pulleys engaged by the driving belts. For convenience in mounting the stud shaft, it is secured directly in the lower portion of the column in parallel relation to the main shaft. To provide an effective individual drive for the machine rather than to employ a line shafting drive connection of the factory type as in the patented machine, the illustrated machine has mounted upon its base an electric motor driver connected to the driven pulleys on the stud shaft by a separate belt. With the use of unenclosed pulleys and belts in a machine of the type indicated, extreme care must be exercised in their installation and use to insure against accidental contact by the operator or by passing objects.

The principal purpose of the present invention is to avoid the hazard present in the use of open belts or pulleys on an individually motor driven machine of the type referred to and to provide a simple, effective and conveniently arranged guard for these parts without rendering the construction of the machine excessively complicated or expensive either in manufacture or in subsequent use. To these ends, the shoe sewing machine hereinafter described has a main sewz:

ing shaft with a clutch thereon including at least one driven pulley, a supporting column in the upper portion of which the sewing shaft rotates, a fixed stud shaft disposed in the lower portion of the column, driving and driven pulleys on the Claims. (Cl. 112*261) stud shaft, together with a belt and belt tightener comprising an arm rotatable on the stud shaft; in which machine is provided a guard plate for the pulleys and belt mounted at its lower end on the stud shaft with the tightener arm in front and formed with an arcuate opening through which the belt tightener may move in performing its function, all of the pulleys being protected behind the guard plate.

These and other features of the invention as hereinafter described and claimed will be apparent from the following detailed description taken in connection with the accompanying drawings, in which Fig. 1 is a view in front elevation partly broken away and in section of a machine embodying the features of the present invention; and

Fig. 2 is a side View of the machine illustrated in Fig. 1, also broken away and partly in section.

The machine illustrated in the drawings is similar to that of the patents above referred to and is a McKay type shoe sewing machine having the usual stitch forming and work engaging devices, including a rotary shoe entering horn 4 and a straight hook needle 5 mounted at the lower end of a needle reciprocating bar 8. The needle bar 8 is guided by vertical hearings in a sewing head it of a hollow main supporting column E2 in which the horn ii is mounted for rotation about a vertical axis. For driving the needle bar and other stitch forming devices, the bar is connected through a pitman M with a crank on a main sewing shaft i5 rotatable in the sewing head portion of the column.

At the rearward end of the sewing shaft i6 is a clutch comprising a brake wheel l8 fixed to the shaft. The brake wheel has an internal conical face engaged by a similar external face on a low speed driven pulley 2d rotating loosely on the sewing shaft. The driven pulley 20 has an internal clutching face engaged by a similar external face on a smaller high speed driven pulley 22 also rotatable on the sewing shaft. For driving the pulleys '28 and 22 they are engaged by a pair of endless belts 2t and 26 extending downwardly therefrom and surrounding respectively a pair of driven pulleys 28 and 30 rotating together on a fixed stud or countershaft 32 disposed in the lower portion of the column in parallel relation to the main shaft. For fixing the stud shaft 32, its forward end is reduced in diameter and threadedly engaged by a clamp nut 34 acting to draw the shoulder between the full diameter portion and the reduced end securely against the inner surface of the machine column at the front side thereof. The central portion of the stud shaft is supported in a close fitting opening at the rearward side of the column.

To drive the driven pulleys 28 and 30, an individual power driver is connected to the column in the form of an electric motor 35 bolted to the base of the column. The motor 35 has a pulley 36 over which a belt 38 runs to a driving pulley 46 connected for rotation with the driven pulleys 28 and 30.

To avoid the necessity of frequently tightening the belt 24, it is engaged between the driven pulleys 20 and 28 by a tightener pulley 42 supported loosely on a pin 44 carried by the upper end of a belt tightener arm 46. The arm 46 is rotatable at its lower end on the stud shaft 32 for adjusting the tension of the belt and is retained in adjusted position by a drawbolt 48 passing through the hub of the arm and'engaging the stud shaft.

As usual with the type of machine of which the one illustrated herein is an example, the moving belts and driven pulleys present a definite hazard to personnel and movable equipment employed in the operation of the machine. To comply with safety regulations all of the driving parts of the present machine are enclosed and shielded from accidental contact in a manner which is both effective for the purpose stated and also is conveniently removable so that the moving parts are accessible for adjustment and replacement purposes.

To these ends, the illustrated machine has arranged behind the column |2 in front of the pulleys and belts a guard plate 50 mounted at its lower end on the stud shaft 32 and secured at its upper end to a metal strap 52 bolted to the head portion of the column. To enable the belt tightener arm to be adjusted on the stud shaft conveniently without dismantling any of the machine parts, the guard plate is disposed with the tightener arm in front of it and is formed with an arcuate opening 54 through which the tightener pulley supporting pin 44 projects, the tightener pulley 42 actually being located behind the guard plate 59 with the other moving parts.

To provide a rigid mounting for the guard plate on the stud shaft and at the same time to afford a conveniently accessible arrangement both for adjusting the tightener arm and assembling or disassembling the guard plate with relation to the machine, the guard plate is connected with the legs of a multi-legged spider 56 secured at its center to the stud shaft, the legs being bolted at 58 to the guard plate. The upper legs of the spider are longer and disposed at a smaller relative angle to each other than the lower ones and all of the legs are arranged to project radially from the center of the spider. Also, the legs are offset rearwardly to provide adequate space for the tightener arm between the forward side of the guard plate and the column l2.

To enable the use of a short shaft on the power driver motor 28 without the necessity of locating any portion of the motor behind the guard plate, the guard plate is offset rearwardly at 60 near its lower end with reversed bends separated sufficiently to bring it close to the motor pulley 36 between the pulley and the motor housing. The motor pulley and its belt 38 only are mounted behind the guard plate and the motor shaft extends through a horizontal slot 62 in the guard plate of suiiicient length to enable belt tightening movement of the motor.

To protect completely the pulleys and belts, a three-sided enclosure 64 is releasably supported on the guard plate. The enclosure includes top and bottom end walls and the sides only are perforated along their central portions, as at 66 for purposes of convenient inspection of the belts and for lightness of construction. For releasably supporting the enclosure 64 on the guard plate, the guard plate carries a series of angle bolts 68, the threaded ends of which pass through slots in the upper end of the strap 52 and in a series of forked clips 10 secured to the guard plate 50. Securement to the guard plate is provided by wing nuts 12 on the angle bolts which enter the forks in the clips.

To protect the upper end of the belt tightener arm 48 against accidental displacement from external contact with it, the arm is shrouded at its pin supporting end by a metal shell 14 bolted to one of the spider legs and disposed to block easy access through the opening 54 to the tightener pulley. Not only does the shell prevent accidental contact with the upper end of the tightener arm but also reduces the possibility of entry through the opening 54 of foreign articles into the space between the guard plate and enclosure.

The nature and scope of the invention havin been indicated in a particular embodiment and having been described, what is claimed is:

1. A shoe sewing machine having a main sewing shaft, a clutch on the sewing shaft comprising a driven pulley, a supporting column in the upper portion of which the sewing shaft is rotatably mounted, a stud shaft disposed in the lower portion of the column in parallel relation to the main shaft, driving and driven pulleys on the stud shaft, a belt connecting the driven pulley of the clutch with the driven pulley on the stud shaft, a tightener pulley acting on the belt between the two driven pulleys, a belt tightener arm rotatable at one end on the stud shaft and a tightener pulley supporting pin on the other end of the arm, in combination with a guard plate for the pulleys and belt mounted at its lower end on the stud shaft with the tightener arm in front and formed with an opening through which the tightener pulley supporting pin projects to support the tightener pulley behind the guard plate.

2. A shoe sewing machine having a main sewing shaft, a clutch on the sewing shaft comprising a driven pulley, a supporting column in the upper portion of which the sewing shaft is rotatably mounted, a stud shaft disposed in the lower portion of the column in parallel relation to the main shaft, driving and driven pulleys on the stud shaft, a belt connecting the driven pulley of the clutch with the driven pulley on the stud shaft, a tightener pulley acting on the belt between the two driven pulleys, a belt tightener arm rotatable at one end on the stud shaft, a tightener pulley supporting pin on the other end of the arm, in combination with a guard plate for the pulleys and belt mounted on the stud shaft with the tightener arm in front and formed with an opening through which the tightener pulley supporting pin projects to support the tightener pulley behind the guard plate and a spider secured at its center to the stud shaft with its legs connected with the guard plate to provide space for the belt tightener arm between the guard plate and the column.

3. A shoe sewing machine having a main sewing shaft, a clutch on the sewing shaft comprising a driven pulley, a supporting column in the upper portion of which the sewing shaft is rotatably mounted, a stud shaft disposed in the lower portion of the column in parallel relation to the main shaft, driving and driven pulleys on the stud shaft, a belt connecting the driven pulley of the clutch with the driven pulley on the stud shaft, a tightener pulley acting on the belt between the two driven pulleys, a belt tightener arm rotatable at one end on the stud shaft, a tightener pulley supporting pin on the other end of the arm, in combination with a guard plate for the pulleys and belt mounted on the stud shaft with the tightener arm in front and formed with an opening through which the tightener pulley supporting pin projects to support the tightener pulley behind the guard plate, a spider secured at its center to the stud shaft with its legs connected with the guard plate to provide space for the belt tightener arm between the guard plate and the column, a power driver connected to the column, a belt running from the power driver to drive the driving pulley on the stud shaft and an offset in the guard plate to provide space in front for the power driver with the power driver belt behind the guard plate.

4. A shoe sewing machine having a main sewing shaft, a clutch on the sewing shaft comprising a driven pulley, a supporting column in the upper portion of which the sewing shaft is rotatably mounted, a stud shaft disposed in the lower portion of the column in parallel relation to the main shaft, driving and driven pulleys on the stud shaft, a belt connecting the driven pulley of the clutch with the driven pulley on the stud shaft, a tightener pulley acting on the belt between the two driven pulleys, a belt tightener arm rotatable at one end on the stud shaft, a tightener pulley supporting pin on the other end of the arm, in combination with a guard plate for the pulleys and belt mounted on the stud shaft with the tightener arm in front and formed with an opening through which the tightener pulley supporting pin projects to support the tightener pulley behind the guard plate, a spider secured at its center to the stud shaft with its legs connected with the guard plate to provide space for the belt tightener arm between the guard plate and the column, a power driver connected to the column, a belt running from the power driver to drive the driving pulley on the stud shaft, an offset in the guard plate to provide space in front for the power driver with the power driver belt behind the guard plate and a threesided removable enclosure releasably supported on the guard plate.

5. A shoe sewing machine having a main sewing shaft, a clutch on the sewing shaft comprising a driven pulley, a supporting column in the upper portion of which the sewing shaft is rotatably mounted, a stud shaft disposed in the lower portion of the column in parallel relation to the main shaft, driving and. driven pulleys on the stud shaft, a belt connecting the driven pulley of the clutch with the driven pulleyon the stud shaft, a tightener pulley acting on the belt between the two driven pulleys, a belt tightener arm rotatable at one end on the stud shaft, a tightener pulley supporting pin on the other end of the arm, in combination with a guard plate for the pulleys and belt mounted at its lower end on the stud shaft with the tightener arm in front and formed with an opening through which the tightenerpulley supporting pin projects to support the tightener pulley behind the guard plate and a shell in front of the guard plate, enclosing the pin supporting end of the belt tightener arm to block access to the tightener pulley through the opening in the guard plate.

OTIS M. HOLMES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 710,612 Richardson Oct. '7, 1902 892,794 Bailey July 7, '1908 1,145,715 Sweeney July 6, 1915 

